Device and method for recovering heat from the environment

ABSTRACT

The invention relates to a device for recovering heat from the environment, for use in underground and underwater construction, wherein in a sheet piling wall ( 2 ) anchored in a subgrade and made of sheet piling wall elements ( 4 ) that can be locked to each other, the sheet piling wall elements ( 4 ) comprise at least one closed hollow space ( 6 ) designed as a heat tube ( 8 ), wherein the heat tube ( 8 ) transfers heat energy drawn from the water or the ground via the sheet piling wall elements ( 4 ) to a heat pump ( 16 ) via a heat exchanger ( 12 ) at the one end ( 14 ) of the heat tube ( 8 ).

The invention refers to a device for recovering heat from the environment as defined in the precharacterizing part of claim 1 and to a method as defined in claim 8.

The use of sheet piling walls in hydraulic engineering and civil engineering is known. Sheet piling walls serve to protect excavations or ridges and may at the same time fulfill a sealing function so that a sealing against water or contaminated ground is also possible. In hydraulic engineering, the sheet piling walls may be used, for example, as quay walls, dock structures for waterways and in embankment protections.

A sheet piling wall is composed of individual sheet piling wall elements rammed into the ground or pressed thereinto under vibration. Most often, the sheet piling wall elements are made of steel. The individual sheet piling wall elements composing a sheet piling wall are connected among each other by means of cooperating locks so that a continuous sheet piling wall can be formed. Upon ramming, each sheet piling wall element is guided laterally by the lock of the last rammed sheet piling wall element and is connected therewith in a force-fitting and water-tight manner. Various sheet piling wall elements made by different manufactures exist. Common sheet piling wall elements are available in lengths ranging from about 6 m to 30 m, for example.

Sheet piling walls are also used in hydraulic engineering as permanent construction elements for quay walls, sluice walls, canals, moles or port basins, as well as for flood protection.

Sheet piling walls formed from sheet piling wall elements of different profiling are known from DE 2819737.

The use of sheet piling walls is preferred, since they can be produced and installed at low cost and, further, are maintenance-free and durable.

It is further known to collect energy present in the environment using heat pumps and to utilize the same for heating or as heat for the preparation of hot water.

Further, heat tubes are known as heat exchangers that allow for a high thermal flow density through the use of evaporation heat from a substance. Heat exchange tubes do not require any additional auxiliary energy, such as a circulation pump, for instance, to move the heat transport medium (working fluid), so that the maintenance effort and the operating costs are minimized thereby.

Heat exchange tubes are known as heat pipes or also as two-phase thermosiphons.

Generally, heat pipes include a hermetically capsulated hollow space, most often in the form of a pipe. The hollow space is filled with a heat transport medium, for the smaller part, that fills the volume of the hollow space in a liquid state and, for the larger part, fills it in a vaporous state.

The field of application of a heat pipe is restricted to the region between the melting temperature and the temperature of the critical point of the working fluid used. A preferred heat transport medium should be useable in a temperature range from −10° Centigrade to +40° Centigrade.

It is an object of the invention to provide a device and a method for recovering regenerative heat from the environment, wherein it is possible to achieve an efficient energy recovery from the environment with the use of structural elements that are required anyway.

The object is achieved with the features of claim 1, as well as of claims 8 and 11.

The invention advantageously provides a device and a method for recovering regenerative thermal energy from the environment by means of a sheet piling wall with integrated heat pipes which can be used, for example, in or immediately at bodies of water such as rivers, lakes or the sea. A heat exchanger arranged at the warmer end of the heat pipes makes it possible to transport the thermal energy drawn from the water or the ground on to a heat pump via a heat exchanger.

It is an essential advantage of such a heat recovery installation that structural elements that are required anyway can be used to draw heat from the environment over their large contact surface. Since the strength of the sheet piling walls is even augmented by the integration of the heat tubes, the mechanical stabilization of banks, subgrades and structures for the prevention of water pollution, for example, is not only fully ensured, but even meets stricter design requirements.

By recovering heat from water, it becomes possible to reduce the temperature of bodies of water, whereby temperature increases due to the introduction of waste water, for example, can be compensated for.

Also with flood protection installations, the additional advantage can be achieved that the structural elements allow for the recovery of energy.

In a preferred embodiment it is provided that the sheet piling wall element is double-walled, and that a heat pipe is integrated in the hollow space formed therein.

The heat pipe may also be formed by a pipe of round or parallelepiped cross section that is fastened or welded to the sheet piling wall.

Preferably, the heat pipe is a CO₂ heat pipe. Heat pipes have an excellent heat transport capacity. CO₂ is the heat transport medium (working fluid) of choice, because of its biological safety.

The thermodynamic design of these heat pipes is such that the two thermodynamic processes, namely the evaporation and the condensation processes, can occur in the closed system without a circulation pump and without any auxiliary energy. The heat pipes only function as condensers and are designed and optimized for that purpose. If they are connected with or fastened to the sheet piling wall as prefabricated units, they themselves do not contribute to an augmented mechanical stability of the sheet piling wall.

Preferably, the heat pipes are arranged in the sheet piling wall portion located in water, but on the side averted from the water. Thus, a protected arrangement of the heat pipes can be achieved, while still allowing the transport of heat to the heat exchanger via the sheet piling wall elements.

Preferably, two thirds of the sheet piling wall are in the soil, while one third is in water.

Nevertheless, the entire sheet piling wall surface is available for heat recovery, regardless of whether it is in contact with water or soil.

The following is a detailed description of embodiments of the invention with reference to the drawings.

In the Figures:

FIG. 1 shows a sheet piling wall used in the field of hydraulic engineering,

FIGS. 2 to 8 show different profiles of a sheet piling wall with integrated heat pipes in cross section.

For the purpose of utilizing the heat stored in a body of water 10 without using water-hazardous media, while still utilizing the high efficiency of the heat pump technology, heat pipes 8 integrated in a sheet piling wall 2 are placed close to the surface in open bodies of water 10 and/or near the same under hydrologic regime.

Due to a new type of heat pipes 8 integrated in sheet piling walls 2, which pipes are installed in open waters 10 and their littoral zones as CO₂ heat pipes or heat pipes 8 filled with a technically equivalent heat transport medium, it is possible even to install sheet piling walls 2 with integrated heat pipes 8, e.g., in rivers and in the sea with reduced effort, in a technically simple manner and at low cost.

The integrated heat pipes 8 are formed by pressure-resistant metal structures dimensioned and manufactured according to predetermined thermal recovery capacities and static requirements. In this context, a plurality of different arrangements is possible, which can be connected among each other. Thus, it is possible to build economically and technically efficient installations with zero emissions that operate without trouble and without impairments to the environment even in long-term operation.

Sheet piling wall elements 4 for a sheet piling wall 2 are known, for instance, as Peiner steel sheet piling walls (cf. product range brochure “Hoesch Stahlspundwände” 1/03 and “Peiner Stahlspundwände” 3/02 of HSP Hoesch Spundwand and Profil, GmbH, Dortmund). These company brochures offer rolled sheet piling wall elements 4 as parts lockable in a watertight manner, depending on the embodiment, which can be connected with each other by means of sheet piling wall locks 42.

These sheet piling wall elements 4 serve, among other things, to support ridges and to protect excavations, dykes, dams and port structures. They have to be able to absorb great horizontal forces that lead to a corresponding bending stress of the sheet piling walls 2 in a direction vertical to the extension of the sheet piling wall elements 4. The decisive factor for the dimensioning generally is the bending stress that is exerted by the lateral pressure from the soil and/or the water and that can be absorbed by the sheet piling wall element 4 via the section modulus. Depending on the load to absorb, these sheet piling wall elements 4 can be connected with similar sheet piling wall elements 4 by means of connection locks 42 such that a closed sheet piling wall 2 of individual sheet piling wall elements 4 can be built with a high section modulus, or they can be used for a sheet piling wall 2 with different sheet piling wall elements 4, where, for example, U- or Z-shaped elements can be arranged in a row using the connection lock 42.

Depending on the required section modulus of the sheet piling wall elements 4, the same are offered essentially in different structural heights with different wall thicknesses.

In prior art different possibilities exist to augment the section modulus of a standard profile in the form of a sheet piling wall element 4 without selecting an economically unfeasible profile or without having to choose an entirely new profile with a duly modified geometry (essentially with respect to the structural height and the wall thickness. In order to avoid these drawbacks, it is attempted to optimize the section modulus according to the requirements while maintaining the geometry of the standard sheet piling wall element 4.

One possibility, known and proven for a long time in practice, is the welding of steel lamellae on one or both flange outer sides of the sheet piling wall element 4 (cf. excerpt from the product range brochure “Peiner Stahlspundwände” 3/02). These lamellae are preferably arranged in the region of the highest bending moment occurring. Welding on lamellae is laborious and entails additional costs due to reshaping work on the sheet piling wall element 4 necessary because of welding tensions occurring.

The sheet piling wall element 4 can be used with a second intermediate plate/lamella welded thereon at a distance from the web, so that the mean section modulus is augmented, while the profile dimensions of the existing standard profile are kept constant and, in addition, the hollow space 6 formed thereby can be used as a heat pipe 8 integrated in the sheet piling wall 2.

Such a heat pipe 8 integrated in a sheet piling wall 2 is advantageous in that even large sheet piling wall structures can economically be given a new, additional use without having to make basic changes to the planned structures and the static requirements thereof. Here, it is further possible to recover regenerative energy.

By an integration of heat pipes 8 in a sheet piling wall 2, a securing structure that is necessary anyway can simultaneously be used for heat recovery.

FIG. 1 illustrates a sheet piling wall 2 composed of a plurality of interlocked sheet piling wall elements 4 anchored in the subgrade or the soil 1. The individual sheet piling wall elements 4 are locked with each other by means of a lock 42, the elements being adapted to form a tight sheet piling wall 2 sealing against water 10.

FIG. 1 is a mere schematic illustration. Typically, about ⅔ of such a sheet piling wall 2 are in the ground 1 and about ⅓ of its length is in water 10.

Preferably, the sheet piling wall elements 4 comprise a heat pipe 8 coupled with the sheet piling wall element 4 in a thermally conductive manner. The heat pipe 8 may be integrated in the sheet piling wall element 4 as a separate component or may be formed in a closed hollow space 6 of the sheet piling wall element 4.

The heat pipe 8 extracts thermal energy from the water 10 or the ground 1 via the sheet piling wall elements 4, and does so preferably over the entire surface of a sheet piling wall element 4. The thermal energy collected at the warmer end 14 of the heat tube 8 is transferred to a heat pump 16 via a heat exchanger 12 and a conduit 18.

As illustrated in FIGS. 2 and 3, the sheet piling wall element 4 may be double-walled to form a hollow space 6, where the heat pipe 8 is formed in the hollow space 6 and the sheet piling wall element 4 forms the limiting walls of the heat pipe 8. The cavities 6 are closed at their lower and their upper ends 14 so that the heat pipe 8 is contained in a hermetically closed hollow space 6.

FIG. 4 illustrates another alternative embodiment, in which the sheet piling wall element 4 on the left in the drawing essentially corresponds to the sheet piling wall elements 4 in FIGS. 2 and 3, and the middle sheet piling wall element 4 illustrates the integration of two heat pipes 8 formed by bridging the sheet piling wall profile in two places.

On the right, FIG. 4 shows a conventional heat pipe 8 connected with a wall element 24 via thermally conductive connection elements 34.

The heat transport medium in the heat pipes 8 is designed for an operating range between about −10° Centigrade and +40° Centigrade and preferably is CO₂.

FIG. 5 shows the heat tubes 8 preferably on the side if the sheet piling wall 2 averted from the water. The embodiment illustrated in FIG. 5 shows a box pile 38 with reinforcements 40 in connection with sheet piling wall elements 4 that each includes a heat pipe 8.

Such box piles 38 serve as supports for a sheet piling wall 2, for example, if high water pressures prevail.

FIG. 6 illustrates an embodiment in which the heat pipes 8 are arranged on one side of another type of profile.

FIG. 7 illustrates a double sheet piling wall 2 supported at a plurality of box piles 38. Here, the heat pipes 8 are arranged on the side of the sheet piling wall 2 averted from the water 10.

FIG. 8 illustrates a sheet piling wall 2 formed by sheet piling wall elements 4 in the form of box sheet piles 40 connected with each other by connection and locking elements 42. Here, as an example, the heat pipes 8 are arranged on one side inside the profile which is I-shaped in cross section. 

1. A device for recovering heat from the environment for use in civil and hydraulic engineering, comprising: wherein a sheet piling wall anchored in a subgrade and made of sheet piling wall elements that can be locked to each other, the sheet piling wall elements further comprises at least one closed hollow space designed as a heat pipe, the heat pipe transferring thermal energy drawn from the water or the ground via the sheet piling wall elements to a heat pump via a heat exchanger at the one end of the heat pipe.
 2. The device of claim 1, wherein at least one vertically extending heat pipe is arranged on a double-walled sheet piling wall element.
 3. The device of claim 1, wherein the at least one vertically extending hollow space is formed by a pipe profile fastened to the sheet piling wall element and closed at the ends.
 4. The device of claim 1, wherein the at least one heat pipe contains a heat transport medium suited for the temperature range from −10° Centigrade to +40° Centigrade.
 5. The device of claim 1, wherein the at least one heat pipe is a CO_(s) heat pipe.
 6. The device of claim 1, wherein the piping wall elements have profiles that comprise wall sections extending in parallel with each other in the longitudinal direction and being angularly offset with respect to each other, wherein, to form the heat pipes, the hollow spaces closed at the ends are formed by wall elements extending in parallel with said wall sections in the longitudinal direction thereof, said wall elements bridging at least two wall sections.
 7. The device of claim 1, wherein, in the portion of the sheet piling wall located in water, the heat pipes are arranged on the side averted from the water.
 8. A method for recovering heat from the environment for use in civil and hydraulic engineering, wherein adapting a sheet piling wall comprising a plurality of sheet piling wall elements to be locked with each other is driven into the ground, forming at least one heat pipe in the sheet piling wall or is fastened thereto in a thermally conductive manner, and wherein the thermal energy extracted by the heat pipe from water or the ground via the sheet piling wall elements is transferred to a heat pump via a heat exchanger at one end of the heat pipe.
 9. The method of claim 8, wherein vertically extending hollow spaces are formed at the sheet piling wall elements, which accommodate heat pipes or form a heat pipe.
 10. The method of claim 8, wherein CO₂ heat pipes are used as the heat pipes.
 11. A sheet piling wall elements of a sheet piling wall comprising: a plurality of sheet piling wall elements adapted to be locked with each other, to be used in civil and hydraulic engineering for receiving at least one heat pipe and for recovering thermal heat from water or the ground over the entire surface of the sheet piling wall elements. 